Function of reinserted abductor muscles after
femoral replacement
A. Giurea, T. Paternostro, G. Heinz-Peer, A. Kaider,
F. Gottsauner-Wolf
From the University of Vienna, Austria
e compared two methods of reconstruction of
the abductor mechanism in 15 patients after
prosthetic replacement of the upper femur, to assess
abductor strength and function.
Six patients in group I had direct fixation of the
gluteus medius tendon and a segment of the original
bone to the prosthesis. Nine patients in group 2 had
the abductor tendon fixed to the iliotibial band. We
assessed clinical function, isometric muscle strength
and muscle cross-sectional area for each patient.
The patients in group 1 had better clinical and
functional results (p = 0.059), with average peak
torques for hip abduction of 92% of that in the
non-operated leg in group 1, and of 57% in group 2.
Group 1 had a mean muscle cross-sectional area of
69% and a mean value of strength per cross-sectional
area of 134% when compared with the control side.
The respective values for group 2 were 52% and 91%.
Direct fixation of the abductor muscles to the
prostheses gave improved function and higher
isometric abductor muscle force.
W
J Bone Joint Surg [Br] 1998;80-B:284-7.
Received 18 July 1997; Accepted 13 August 1997
Prosthetic replacement of the upper femur after tumour
resection or at revision arthroplasty of the hip may be
1-3
associated with considerable loss of muscle function.
The resection of malignant bone tumours often requires
extensive removal of soft tissues.
The reconstruction of bone defects with megaprostheses
A. Giurea, MD, Consultant
F. Gottsauner-Wolf, MD, Associate Professor
Department of Orthopaedics
T. Paternostro, MD, Consultant
Department of Physical Medicine and Rehabilitation
G. Heinz-Peer, MD, Consultant
Department of Radiology
A. Kaider, MSc, Statistician
Department of Medical Computer Science
University of Vienna, Währinger-Gürtel 18, A-1090 Vienna, Austria.
Correspondence should be sent to Dr F. Gottsauner-Wolf.
©1998 British Editorial Society of Bone and Joint Surgery
0301-620X/98/28179 $2.00
284
is well established, but there are technical problems with
3-6
the attachment of muscles and tendons to the prosthesis.
Inadequate reattachment will cause considerable loss of
5
function and loss of joint stability. Various techniques have
6,7
been devised, but the treatment of tumours produces
special problems, and soft-tissue attachment with or with6,7
out the use of bone blocks is not always successful.
We studied the differences between two surgical methods
of refixation of the gluteus medius. In one group the gluteal
muscles were fixed to the iliotibial band and in the other
they were attached directly to the prosthesis.
Patients and Methods
We investigated 15 patients following the prosthetic
replacement of the femur with reconstruction of gluteus
medius, after an average of 44 months (12 to 92). There
were four men and 11 women with a mean age at operation
of 36 years (10 to 83). Five patients had total replacement
of the femur and ten replacement of only the proximal part.
The resections were for malignant bone tumours in 12 and
as part of a revision hip arthroplasty in three (Table I). The
KMFTR-prosthetic system (Kotz Modular Femur and Tibia
Reconstruction System; Howmedica, Kiel, Germany) was
used in each patient. The 32 mm head was of aluminium
oxide ceramic. Either a titanium-alloy conical threaded cup
(CSF, Allo Pro; Sulzer Medical, Winterthur, Switzerland) or
a cemented polyethylene cup (Müller; Protek, Winterthur,
Switzerland) was used. When acetabular reconstruction
was not required we used a bipolar head (Howmedica,
Rutherford, New Jersey).
The six patients in group 1 had reattachment of the
medial gluteal tendon to the prosthesis using a bone block
Table I. Indications for femoral replacement in 15 patients
Total
Tumour
12
Ewing's sarcoma
5
Osteogenic sarcoma
4
Metastases
2
Malignant fibrous histiocytoma 1
Revision
Total
Proximal
femoral
replacement
7
3
1
2
1
Total femoral
replacement
5
2
3
---
3
3
--
15
10
5
THE JOURNAL OF BONE AND JOINT SURGERY
FUNCTION OF REINSERTED ABDUCTOR MUSCLES AFTER FEMORAL REPLACEMENT
285
Surgical techniques for reconstruction of the gluteus medius.
Figure 1a – Group 1: a bone block from the greater trochanter
with the insertion of gluteus medius is fixed by a polyethylene spiked plate and screws to a KMFTR prosthesis. Figure
1b – Group 2: reattachment of gluteus medius to the iliotibial
band.
Fig. 1a
Fig. 1b
8
Table II. Functional evaluation system according to Enneking et al
Score
Pain
Function
Emotional
acceptance
Supports
Walking
Gait
5
4
3
2
1
0
None
Intermediate
Modest
Intermediate
Moderate
Severe
No restriction
Intermediate
Recreational restriction
Intermediate
Partial disability
Total disability
Enthusiastic
Intermediate
Satisfied
Intermediate
Accepts
Dislikes
None
Intermediate
Brace
Intermediate
Cane or crutch
Canes or crutches
Unlimited
Intermediate
Limited
Intermediate
Indoors only
Unable unaided
Normal
Intermediate
Minor cosmetic
Intermediate
Major cosmetic
Major handicap
Fig. 2b
Fig. 2a
which included the natural insertion; four patients had
fixation by a spiked polyethylene plate and two screws,
which is provided routinely with the prosthesis (Fig. 1a).
The nine patients in group 2 had gluteus medius sutured to
the iliotibial band with no direct fixation to the endoprosthesis (Fig. 1b).
All patients were examined clinically and radiologically,
8
using the evaluation system of Enneking et al (Table II).
The isometric muscle strength of hip abduction and of foot
dorsiflexion were measured in both legs of 13 patients by
computerised dynamometry using a Cybex 6000 testing
9-12
machine (Lubex Inc, Ronkonkoma, New York).
Two
VOL. 80-B, NO. 2, MARCH 1998
CT scans of a 20-year-old woman with endoprosthetic
replacement of the left proximal femur showing (a) a scout
view with the levels indicated and (b) the cross-sectional
area of gluteus medius and gluteus maximus on the control
side (1 and 2) and on the operated side (4 and 3).
patients, one aged 80 years (group 1) and the other aged 91
years (group 2), were unable to perform the dynamometric
tests. The tests were repeated three times on each leg and
the highest peak torque was recorded as the isometric
muscle strength. The foot dorsiflexion was tested to assess
any overall weakness within the operated leg caused by
postoperative immobilisation.
In 11 patients, the cross-sectional area of the gluteus
medius was measured on each side from CT scans (Tomoscan SR 7000; Philips, Eindhoven, The Netherlands) (Fig.
2). From three to five scans were taken in steps of 10 mm
starting at the proximal end of the endoprosthesis, the
286
A. GIUREA,
T. PATERNOSTRO,
G. HEINZ-PEER,
Table III. Clinical results showing the percentages of
patients with excellent and good results on the system
8
of Enneking et al
Group
1 (n = 6)
2 (n = 9)
Pain
Function
Emotional acceptance
Supports
Walking
Gait
83
67
83
67
83
67
89
56
89
56
78
33
Total rating
71
59
A. KAIDER,
F. GOTTSAUNER-WOLF
compared with the control side (Fig. 4). The strength of hip
abduction per unit of cross-sectional area in group 1 was
134% (58 to 272) of that on the control side, and in group
2 91% (33 to 182) (p = 0.21; Fig. 4).
Discussion
Clinical evaluation showed an average Enneking rating
of 71% (20 to 97) in group 1 and of 59% (37 to 77) in
group 2 (p = 0.059) (Table III). All the implants were
radiologically stable with no signs of loosening.
The isometric muscle strength of hip abduction in group
1 (five patients) showed a mean peak torque of 92% (30 to
185) compared with the non-operated leg. The corresponding value in group 2 (eight patients) was 57% (20 to 99)
(Fig. 3), but the difference did not reach statistical significance (p = 0.18). The mean peak force was 65.6 Nm (24
to 142) in group 1 and 39.2 Nm (14 to 72) in group 2. The
mean peak torque of foot dorsiflexion was 98% (51 to 158)
in group 1 and 88% (55 to 171) in group 2, again compared
with the non-operated leg (p = 0.38; Fig. 3).
The mean cross-sectional area of the gluteus medius on
the operated side was 69% (42 to 89) in group 1 (five
patients) and 52% (0 to 88) in group 2 (six patients) when
Direct fixation of the gluteus medius to the prosthesis gave
improved overall clinical outcomes, particularly of gait. The
refixation of muscles to the prosthesis appeared to improve
the quality of life and reduce the need for external aids.
Isometric measurement of muscle force has been reported to correlate well with the function of the replaced hip as
1
assessed by gait analysis. We found that isometric muscle
strength was greater in group 1 after direct muscle fixation
to the prosthesis, and also found that gluteus medius had a
larger mean cross-sectional area in this group. This may
have been due to greater activity in the reinserted muscle,
although loss of the muscle which had been resected could
have influenced the result. There was, however, also a
higher muscle strength per unit of cross-sectional area in
group 1. Other factors which affect muscle function include
13,14
and the positioning of the
the use of physiotherapy
2,9,15
prosthesis
which we did not assess.
Muscles which were not fixed to the prosthesis, but to
the tensor fascia, showed reduced strength per unit of crosssectional area compared with muscles attached to the prosthesis. The power of abduction is greater when there is
7,12,16
direct transfer of load to the femoral prosthesis.
The
fixation is better and the risk of dislocation, very real after
5
tumour resection, is probably also reduced.
We recommend that the remaining greater trochanter
with the insertion of the gluteal tendon is fixed directly to a
femoral prosthesis. This is feasible in most revision arthroplasties; tumour prostheses can usually be adapted to allow
such fixation of muscle and tendon.
When malignant tumours are resected, the bony insertions of the abductor muscles are usually removed with the
tumour to achieve safe surgical margins. Despite this, we
recommend the refixation of remaining soft tissue directly
Fig. 3
Fig. 4
Box plots (±SD) for isometric muscle strength (Nm) of hip abduction and
foot dorsiflexion in both groups, as percentages of the normal side.
Box plots (±SD) for the cross-sectional area of gluteus medius and strength
per cross-sectional area in both groups, as percentages of the normal side.
circumferences of the gluteal muscles were digitised and
2
the area was calculated in mm . The data from the operated
side were compared with those from the non-operated side,
and the muscle strength of hip abduction was normalised to
the cross-sectional area of the gluteus medius.
For statistical analysis we used exact Wilcoxon rank-sum
tests to compare differences between the two groups. A p
value <0.05 was considered significant.
Results
THE JOURNAL OF BONE AND JOINT SURGERY
FUNCTION OF REINSERTED ABDUCTOR MUSCLES AFTER FEMORAL REPLACEMENT
to the prosthesis, provided that an appropriate means of
fixation is available. This should provide stable initial
attachment and have a porous coating to allow secondary
biological ingrowth of bone. It has been shown experimentally that appropriate techniques can achieve a biological
7
link between muscle, tendon, and prosthesis, but that this
provided only about one-third of the pull-out strength
7
recorded for bone-block fixation.
No benefits in any form have been received or will be received from a
commercial party related directly or indirectly to the subject of this
article.
References
1. Berman AT, Bosacco SJ, Israelite C. Evaluation of total knee
arthroplasty using isokinetic testing. Clin Orthop 1991;271:106-13.
2. Delp SL, Wixson RL, Komattu AV, Kocmond JH. How superior
placement of the joint center in hip arthroplasty affects the abductor
muscles. Clin Orthop 1996;328:137-46.
3. Chao EY, Sim FH. Modular prosthetic system for segmental bone and
joint replacement after tumor resection. Orthopedics 1985;8:641-51.
4. Kotz R, Ritschl P, Trachtenbrodt J. A modular femur tibia reconstruction system. Orthopaedics 1986;9:1639-52.
5. Sim FH, Chao EYS. Hip salvage by proximal femoral replacement.
J Bone Joint Surg [Am] 1981;63-A:1228-39.
6. Gottsauner-Wolf F, Egger EL, Markel MD, Schultz FM, Chao
EYS. Fixation of canine tendons to metal. Acta Orthop Scand
1994;65:179-84.
7. Gottsauner-Wolf F, Egger EL, Schultz FM, Sim FH, Chao EY.
Tendons attached to prostheses by tendon-bone block fixation: an
experimental study in dogs. J Orthop Res 1994;12:814-21.
VOL. 80-B, NO. 2, MARCH 1998
287
8. Enneking WF, Dunham W, Gebhardt MC, Malawar M, Pritchard
DJ. A system for the functional evaluation of reconstructive procedures after surgical treatment of tumours of the musculoskeletal
system. Clin Orthop 1993;286:241-6.
9. McGrory BJ, Morrey BF, Cahalan TD, An KN, Cabanela ME.
Effect of femoral offset on range of motion and abductor muscle
strength after total hip arthroplasty. J Bone Joint Surg [Br] 1995;
77-B:865-9.
10. Petschnig R, Baron R, Kotz R, Ritschl P, Engel A. Muscle function
after endoprosthetic replacement of the proximal tibia: different techniques for extensor reconstruction in 17 tumor patients. Acta Orthop
Scand 1995;66:266-70.
11. Tsuboyama T, Windhager R, Dock W, et al. Knee function after
operation for malignancy of the distal femur: quadriceps muscle mass
and knee extension strength in 21 patients with hinged endoprostheses. Acta Orthop Scand 1993;64:673-7.
12. Minns RJ, Crawford RJ, Porter ML, Hardinge K. Muscle strength
following total hip arthroplasty: a comparison of trochanteric osteotomy and the direct lateral approach. J Arthroplasty 1993;8:625-7.
13. Johnsson RA, Carlsson A, Kisch K, et al. Function following mega
total hip arthroplasty compared with conventional total hip arthroplasty and healthy matched controls. Clin Orth Rel Res 1985;
192:159-67.
14. Horstmann T, Martini F, Mayer F, Sell S, Knak J, Zacher J.
Strength of muscles surrounding the hip joint and gait in patients
following implantation of a cementless hip endoprosthesis. Z Orthop
Ihre Grenzgeb 1995;133:562-7.
15. Huang CH, Cheng CK, Lee YT, Lee KS. Muscle strength after
successful total knee replacement: a 6- to 13-year follow-up. Clin
Orthop 1996;328:147-54.
16. Horwitz BR, Rockowitz NL, Goll SR, et al. A prospective randomized comparison of two surgical approaches to total hip arthroplasty.
Clin Orthop 1993;291:154-63.